Gear finishing and crowning machine



Nov. 14, 1944. E. w. MILLER GEAR FINISHING AND CRQWNING' MACHINE 5 Sheets-Sheet 1 Filed March 18, 1941 (PE F Nov. 14, 1944. E. w. MILLER GEAR FINISHING AND CROWNING MACHINE F iled March 18, 1941 s Sheets-Sheet 2 Nov. 14, 1944. E. w. MILLER 2,

' GEAR FINISHI NG AND CROWNING MACHINE Filed March 18, 1941 5 Sheets-Sheet 3 Patented Nov. 14, 1944 GEAR FINISHING AND CROWNING MACHINE Edward W..Mille1-, Springfield, Vt., assignor a The Fellows Gear Shaper Company, Springfield, Vt., a corporation of Vermont Application March "18, 1941, Serial No. 383,931

(01. sic-1.6)

11 Claims.

' The present invention relates to machines for finishinggears to prescribed toothforms and dimensionsby shaving, lapping or burnishing. It is more particularly concerned with means for crowning the teeth of the gears, i. e., making their ends of less thickness than their mid portions with a gradual reduction of thickness, in the course of the finishing operation. In its main characteristics the invention is the same as that disclosed in my pending application Serial No. 266,854, filed April 8, 1939, and as to all common subject matter this application is a continuation of the preceding one. The present invention, however, includes an'improvement over the said prior application in respect to the means for effecting oscillation of the work piece about an axis transverse to its own axis, during the relative reciprocation between the work piece and finishing tool which accomplishes the finishing action; and it includes means for shifting the axis of such oscillation whereby to controlthe degree of crowning formation which is given to the work gear teeth.

The general principles and particulars of the invention are fully described in the following specification with reference to drawings of a specific machine exemplifying oneform of the invention. a

In these drawings- 7 Fig. 1 is a plan view of the machine referred to;

Fig. 2 is a detail cross section on line 2-2 of Fig. l; I

Fig. 3 is apartial front elevation of the machine;

Fig. 4 is a partial rear elevation of the machine with partsbroken away and shown in section;

Fig. 5 is an elevation of the right hand end of the machine; f

Figs. 6 and 7 are diagrammatic views showing the performance of the crowning action when the work piece is tilted about different axes of oscillation;

Figs. 8 and 9 are sectional views taken on line 8-8 of Fig. 6 and line 99 of. Fig. 'lprespectively, showing in exaggerated manner the different degrees of crowning given/to the teeth of the work gear consequent upon oscillation of the latter about such different axes.-

Like reference. characters designate the same parts wherever they occur in all the figures.

its marginsi on a base 6.; The finishing tool T is here represented as of the same character and constructionas that shown in my said prior application; that is, a shavingtool composed of a series of disks having teeth with cutting edges of outlines conjugate to the tooth forms to be generated in the finished work piece, which disks are alined axially on' a toolspindle 'l with corresponding teeth of each in alinement with one another. The alinem'ent of such corresponding teeth may be straight and parallel with the axis of the spindle or helical, depending on whether the work gear is ajspur'or helical gear. But shaving tools of other construction,'lapping tools, and burnishing tools maybe used in this situation in place-of the specific tool thus described.

The tool spindle I is supported rotatably in a holder 8; and the latter is-secured to a carriage 9 supported to reciprocate-in guides Ill and H on a depth feed slide. or carriage support l2 which rests on, the base 6 with provisions for guided movement in a straight line toward and away from the tablet.

The head and. tail stocks Sand 4 are engaged with guideways I3 and I4 on the table 5 parallel to the axis of. the centers, so. that gears of different dimensions and variously mounted on different arbors or shafts can all be located in a given working position, with the axes of such work pieces always in the same line.- The path of thecarriage 9-, defined by the guideways l0 and ll, is parallel to the neutral position. of the axis of the centers 1 and 2; and the holder '8 is coupled to the carriage 9 in a manner such that-the tool spindle 1, and consequently the axis of the tool T, may be adjusted angularly about an axis perpendicular to its own axis and to the neutral position of the axis of the centers, and thereby located either in the same plane with the axis of the centers or to limited degrees of inclination in either direction from the common plane. The axis of such angular adjustment is represented by the "broken line C'L in Fig. 2. To permit of such adjustment and maintain the spindle in different adjustments, the holder 8 has a cylindrical boss l5 coaxialwith the Iine'CL and a flange IS in a plane perpendicular to. saidline; The boss fits rotatably a 'comple'mentalrecess in the carriage 9; and the flange It bears against a plane surface on the forward' side of I the carriage and is held tightly against such surface by releasable clamps IT. The tool is located on thespindle so that itsopposite ends are at opposite sides of the line C--L; and the limits of the stroke of the carriage 9 are established with respect to the working location of the gear to be finished so that the line CL lies midway between the ends of the work gear when the carriage is in mid stroke. This is the relationship which obtains when the teeth of the work gear are to be in this type of machine the work is driven rotatably by the tool (or, conversely, the tool by the work piece), continuous mesh is necessary to control such rotation and ensure correct engagement v of the mating teeth. v

The mechanisms for rotatably driving the spindle I, reciprocating the carriage 9 and advancing the depth feed slide 12 here shown are the same as those fully described in my prior application Serial No. 266,854 and need only brief description here; reference being directed to the prior application for explanation of such particulars as may be omitted from this description.

A motor [8 mounted in the slide I2 drives a shaft l9 by a belt and pulley drive. 20. .Shaft i9 carries a changeable pinion 2| which meshes with a changeable gear 22 in .splined engagement with a shaft 23. A pinion 24 on shaft 23 meshes with teeth on one face of a double facegear 25, rotatably mounted onthe spindle holder '8 coaxial with the line CL; and the teeth on the opposite face of gear 25 mesh with and drive a pinion '26 on the tool spindle I.

A motor 21 in the base drives a count-ershaft 28 by a belt 29 (Fig. 4) and shaft 28 drives a shaft 30 by a belt 3!. Shaft 3!) carries a change gear 32 meshing with change gear 33 on a short shaft 34, on which a pinion 35 is secured. A face gear 36 is in mesh with pinion 35, and is connected with a disk 31 carrying a radially adjustable crank pin 38 to which is connected one end of a bar 39, having rack teeth'40 meshing with a gear 4] on a shaft 42. Bar 39 is movable endwise in a guide 43., which is pivoted on Shaft 28 also rotates an alined shaft 46 at a slow rate by means of a speed reducing differ-' ential gearing 41 of known character, consisting of connected pinions carried by an eccentric 'pivot 48 on the shaft 28 and meshing with a sta- ,tionary internal gear 49 and an internal gear 50 secured to shaft 46, ofrespectively different gear ratios. Shaft 46 drives a parallel shaft 5| through change gears 52, 53, and shaft 5| car ries a depth feed cam 54 which bears on aroll 55 carried'by the arm 56 of a. two armed lever. The second arm 51 of said lever carries rotatably a self locking worm 58 in mesh with a gear 59 secured to a shaft 60 (on which the lever is arranged to swing, as on a pivot), which shaft 5 also carries a gear 6| meshing with an intermediate gear 6.2, pivoted on a stationary part of the base in mesh with a rack 63 secured to the slide 12. A stron spring 64 between the arm 56 and a stationary abutment holds roll 55 against the cam. Said cam, having a rise through a large part of its circumference, which may be a con-' tinuous curve or formed in steps, thus advances the tool toward the work at a slow rate which may be varied by changing the gears 52 and 53. The depth feed slide or carriage l2 may be located at different starting points, to accommodate work gears of different diameters, by rotation of worm 58, effected by a manually rotatable shaft section 64l, accessible at the front of the machine, which is connected by a universal joint 65, telescopic shaft sections 66, 61, and universal joint 68 with a shaft section 69 to which the worm is secured.

, By means of the mechanisms just described, the tool is rotated and reciprocated at speeds which have been determined as efficient for shaving or other type of finishing action which is performed by the selected type of tool, the work piece being rotated by the gear action of the intermeshing teeth; and the tool is slowly fed to the prescribed depth into the work piece. In

order to give the finished ear teeth a crowned formation, the work holder (table 5) is gradually tilted back and forth to either side of its neutral position, in which it is parallel to the path of reciprocation of carriage 9, about an axis perpendicular to the plane established by the axis of centers I and 2 and the pitch point of the tool and Work, in time with the reciprocations .of the tool. The axis of tilting is represented by the broken lin P-A in Fig, 2, such line coinciding with the axis of a pivot 10, engaged with the base and with the work table 5 in a manner presently described. This pivot may beshifted ,to place the pivot axisP-A in intersecting relation with the work center axis, or at either side of the work center axis toward or away from the tool, to vary the degree of crowning. In all of its positions the axis P--A is perpendicular to the plane in which line CL lies and is moved by reciprocation of the tool carriage. The plane (or planes) on which themargins of the table are supported on the base is (or are) perpendicular to axis PA and parallel to the plane established by the work axis and pitch point.

The manner, timing and effect of such tilting movement of the work are illustrated in an ex aggerated way by Figs. 6, 7, 8 and 9. In these figures W represents a work piece and t represents one of its teeth. The timing of the crowning tilt is such that, when the tool is in mid stroke, the work ear axis is parallel to the path of the tool. When the tool moves thence to the right, the work is tilted gradually in counter-clockwise rotation until the tool reaches the end of its stroke (being then substantially in the situation shown in Figs. 6 and '7). As the tool moves to the left from its extreme right hand position, the work is tilted in clockwise rotation, becoming parallel to the tool path and then being inclined to the opposite slant, in increasing degree until the tool reaches the opposite end of its stroke. In this way the opposite ends of the gear teeth 1. are alternately entered more deeply between the tool teeth than the mid portions, and are made thinner; and their opposite side faces f, f are made longitudinally convex. When the pivot axis P-A passes through the center of the gear, as illustrated in Fig. 6, the faces I and f are given a certain character of curvature. When the pivot axis is shifted away from the tool, as shown in Fig. '7, the faces 1, f are crowned with a flatter curvature, illustrated by comparison of Figs, 8 and 9; and when the pivot axis is shifted toward the tool, the curvature of the tooth faces is more convex,relatively, than that of the first mentioned condition.

The novel features of the present invention, as compared with the disclosure of my before mentioned parent application, consist in an improved means for imparting this tilting oscillation of the work, and a means for shifting the axis of oscillation toward and away from the tool. The pivot 10 is mounted in a slide H which occupies a guideway 72 in the base and is held therein by retaining bars 13. A second slide, 14, resting on slide H, receives the upper end of the pivot and is confined in a guideway 15 in the under side of the table 5. Guideway 1'2 extends from front to rear perpendicular to the path of the tool carriage, and guideway 15 is parallel to it when the table is inits neutral position. Bolts 15 pass through the table, and have heads I1 located in T slots 18 in the upper portion of slide it; and nuts 19 on said bolts serve to clamp the slide 14 releasably to the work table. A screw 80 is engaged with a threaded passageway in slide II and is rotatable in a bushing 8|, secured to the base, wherein it is confined against endwise movement by a thrust bearing shoulder 82. This screw may be rotated by a wrench applied to its outer end, and serves to shift the pivot III in or out when the clamp nuts 19 are loosened.

The tilting movement previously described is imparted to the table by a worm gear segment 83 secured to one end of the table and meshing with a worm 84 which is driven from rock shaft M! by a sprocket and chain, or link belt drive,' 85,

85, B1, shaft'BB and changeable gear train 89,

ment 83 may be accurately alined with the axis of pivot 70 (in a line radial to the pivot and parallel to the common axis of centers I and 2) when the latter is shifted in or out, the segment is secured adjustably to the edge of the table by means of screws 94 threaded into tapped holes in the table through slots, extending parallel to th axis of the worm 83, in the base portion of the segment, said screws having heads which overlap the boundaries of said slots and serve to clamp the segment securely in its various adjustments. The segment is correctly alined with the pivot by the aid of gauge blocks of different lengths, one of which is shown at 95 between a removable abutment 95 on the machine base and the nearer end of thesegment base. When the segment has thus been positioned to accord with the position of the pivot, and made fast by setting up screws 94, the gauge block 95 and abutment 95 are removed. Angular adjustment ,of the worm 84, to accommodate such shifting of the gear segment, may be effected by turning shaft 93 by a wrench applied to its end, the gear 92 thereon being loosened to permit such rotation. Hold down bars 91 are secured to the machine base overlapping flanges on the ends of the table, with sufficient clearance to permit the prescribed swinging movement of the table through the small angle which is sufficient for crowning.

It will be apparent that the features constituting this invention may be applied to machine combinations diflering'in many respects from the specific machine here illustrated. All such operative equivalents of the combinations and subcombinations herein described are within the scope of the protection which I claim. It will further be evident that with th spindle 1' parallel to the direction of its reciprocation, the work piece may be mounted on the spindle and the tool mounted between the centers I and 2, with exactly like results to those herein described. Thus the invention comprehends reversals in the relationship of the tool and work, and of the means for imparting movements to either or position of the axis ofrotation of such gear or tool, a spindle mounted rotatably on said carriage adapted to hold a toothed finishing tool, or a work gear, in position to mesh with the gear or tool, respectively, which is mounted rotatably on the befor named holding means, a pivotal connection between the base and table, the axis of said pivotal connection being perpendicular to the plane established by the axis of said holding means and the meshing point of tool and work, and being located in a. plane, perpendicular to said rotational axis, between the ends of the gear or tool supported by the said holding means, means for swinging the table about said pivotal connection to opposite sides of the neutral position thereof, comprising a gear segment secured to the table and a worm meshing with said segment, and correlated driving means supported by the base independently of the table for simultaneously reciprocating the carriage and turning the worm back and forth about its axis of rotation.

2. A gear finishing machine as set forth in claim 1, combined with means for shifting said pivotal connection relatively to both the base and the table toward and away from the path of the carriage.

3. A gear finishing machine as set forth in claim 1, combined with means for shifting the pivotal connection toward and away from the path of the carriage, together with provisions for adjusting said gear segment in parallel with the adjustments of the pivotal connection.

4. In a gear, finishing machine, a base, a table supported on said base and pivotally connected therewith for oscillative movement about an axis substantially perpendicular to the width and length dimensions of the table, a carriage mount ed to move in a path substantially parallel to the length dimension of the table, a gear segment secured to one end of the table across a radius of th pivot axis which is substantially parallel to the path of said carriage, a worm meshing with said segments, correlated mechanisms arranged to reciprocate the carriage and simultaneously rotate the worm in opposite directions, and holding means on the table and carriage respectively, one of which is adapted to support a. gear for rotation about its axis and the other to support rotatably a tool having teeth conjugate to the teeth of the gear, said supporting means being located to hold the tool and gear in mesh 5. In a gear finishing machine, a base, a table supported on said base, slides between th base and table contiguous to one another, one slide being movable in a, guideway in the base and the other slide in a guideway in the table, a pivot connection between the slides having its axis arranged substantially perpendicular to the length and width dimensions of the table, holding means on the table arranged to support a work piece rotatably with its axis substantially perpendicular to said pivot axis and to the guide- Way in the base, a carriage guided to move in a path parallel to said axis of rotation, and correlated means for reciprocating the carriage and simultaneously swinging the table in opposite directions to incline the axis of rotation to the path of the carriage, first in one and then in the opposite direction of inclination.

6. In a gear finishing machine, a base, a table supported on said base, slides between the base and table contiguous to one another, one slide being movable in a guideway in the base and the other slide in a guideway in the table, a pivot connection between the slides having its axis arranged substantially perpendicular to the length and width dimensions of the table, holding means on the table arranged to support a work piece rotatably with its axis substantially perpendicular to said pivot axis and to the guideway in the base, a carriage guided to move in a path parallel to said axis of rotation; correlated means for reciprocating the carriage and simultaneously swinging the tablein opposite directions to incline the axis of rotation to the path of the carriage, first in one and then in the opposite direction of inclination, and means for shifting the assemblage of slides and pivot toward and away from the path of the carriage.

7. In a gear finishing machine, a base, a table supported on said base, a carriage supported for reciprocating movement in a prescribed path, a slide in guided engagement with the base for movement toward and away from said path, a second slide in guided engagement with the table, a pivot engaged with both slides arranged with its axis perpendicular to the length and width dimensions of the table and at one side of said path, a gear segment secured to the table substantially alined with a radius of the pivot parallel to said path and being adjustable on the tabl to maintain a similar alinement with the pivot when the latter is shifted toward and away from the carriage path, and means for supporting a gearrotatably with its axis substantially parallel to the path of the carriage and perpendicular to the pivot axis.

8. A gear finishing machine comprising the combination of a-carriage mounted to reciprocate in a'given path, means for so reciprocating said carriage, a normally stationary table, means on the carriage and table, respectively, adapted to hold rotatably elements comprising a gear-like finishing tool and a work gear with the element that is so mounted on the carriage in mesh with the element mounted on the table, said means on the table being parallel to the path of the carriage when the table is in its neutral position,

a pivotal support for said table arranged with its axis substantially perpendicular to the plane established by the rotational axis of the elementsupporting means of the table and the pitch point between said elements, the table being angularly movable about said pivotal support from said neutral position to different angles at either side of the neutral position, and means for shifting said pivotal support relatively to the said rotational axis of the supporting means on the table and toward and away from the path of the carriage.

9. A gear finishing machine comprising the combination with a carriage mounted to reciprocate in a given path, means for so reciprocating said carriage, a normally stationary table, means on th carriage and table, respectively, adapted to hold rotatably elements comprising a gearlike finishing tool, and a work gear, with the element that is so mounted on the carriage in mesh with the element mounted on the table, said means on the table being parallel to the path of the carriage when the table is in its neutral position, a pivotal support for said table arranged with its axis substantially perpendicular to the plane established by the rotational axis of the element-supporting means of the table and the pitch point between said elements, the table being angularly movable about said pivotal support from a neutral position to different angles at either side of such neutral position, and means for shifting said pivotal support toward and away from the path of the carriage without changing the location of the table With respect to the carriage path.

l0. A gear .finishing machine comprising a base, a table supported on said base, holding means on said table adatped tosupport a work gear or a toothed finishing tool rotatably a carriage guided to move in a path parallel to the neutral position of the axis of rotation of such tool or gear, a spindle mounted rotatably on said carriage adapted to hold a toothed finishing tool, or a work gear, in position to mesh with the gear or tool, respectively, that is mounted rotatably on the before named holding means, a pivotal connection between the base and table arranged with its axis perpendicular to the plane established by the axis of said holding means and the meshing point of tool and work, said axis being located also in a plane, perpendicular to said rotational axis, between the ends of the gear or tool supported by said holding means, a gear segment secured to the table, a worm meshing with said segment, said segment and worm constituting means for swinging the table about said pivotal connection so as to place the before named axis of rotation in the neutral position thereof 

